Meteorologist Paul Douglas writes about Minnesota weather daily, trying to go beyond the "highs" and "lows" of the weather story to discuss current trends and some of the how's and why's of meteorology. Rarely is our weather dull - every day is a new forecast challenge. Why is the weather doing what it's doing? Is climate change a real concern, and if so, how will my family be affected? Climate is flavoring all weather now, and I'll include links to timely stories that resonate with me.
Saturday, April 26, 2014
Wet Weather Ahead
Just the Messenger By Paul Douglas
The Polar Vortex is long gone, but like nagging muscle memory, the jet stream continues to sag unusually far south for late April. It is late April, right? May will arrive with a thud; enough cold air aloft for a chance of wet snow by the middle of next week - as I enter the FBI Witness Protection Plan.
The good news: our drought is fading fast, and all this chilly weather is inoculating us from severe storms. A major tornado outbreak is likely later Sunday from near Dallas to Little Rock and Memphis as moisture from the Gulf of Mexico combines with powerful, shifting winds aloft, leading to spinning "supercell" thunderstorms capable of sustaining warm updrafts long enough to spin up large, violent tornadoes.
It's been a relatively quiet tornado season so far, but that may change in the coming days.
A nearly stationary storm will soak thirsty yards & fields with 1-2 inches of rain between now and Thursday, with high temperatures holding in the 40s; nearly 20F colder than normal.
Surface temperatures may approach freezing by midweek, and a little slush can't be ruled out during the nighttime hours.
Keep the faith: GFS guidance shows 70s returning the second week of May.
SATURDAY NIGHT: Mostly cloudy with showers developing. Low: 40
SUNDAY: Rainy, windy and foul. High: 47. Winds: E 20-30.
SUNDAY NIGHT: Sideways rain. Low: 43. Winds: E 20-30.
MONDAY: More rain, feels like early March. High: 46
TUESDAY: Storm stalls, more rain. Wake-up: 40. High: 43
THURSDAY: What May? Sloppy Mix Possible. Wake-up: 35. High: 42
FRIDAY: Peeks of sun, hints of spring return. Wake-up: 37. High: 56.
SATURDAY: Still unsettled, passing shower. Wake-up: 40. High: 57.
This Day in Weather History
2002: Heavy snow over the Twin Cities and central Minnesota. Chanhassen got half a foot. Vivid lightning seen with the snow during the evening.
1996: Low of 9 degrees at Embarrass. Ice was still on some central and most northern Minnesota lakes.
1921: Late season blizzard at Hibbing. The temperature was 75 degrees three days before.
SUNRISE 608 AM SUNSET 813 PM
Minneapolis Averages for April 27
Average High: 63F
Averge Low: 42F
Moon Phase for April 27th at Midnight
1 Day Before New Moon
Wet Weather Ahead
"Tonight will mark the start of an extended wet period. After the rain moves in tonight, periodic showers and isolated thunderstorms will persist through next week. Rainfall totals of 1.5 to 3 inches will be common across the region during this wet period. In addition, strong winds and cool temperatures will accompany this storm system with highs in the 40s and 50s and lows in the 30s and 40s through the end of April."
Rain in the Desert
I'm spending some time with my family in Arizona and what might have been 'normal' to me, was anything but for the locals here in Phoenix. The last time there was measurable rain in Phoenix, AZ was in early March. Temperatures in the 60s also led to several complaints about how cold it was. While my mother (former Minnesotan) looked like she was dressed for a winter Olympic competition, I was in shorts and flip-flops.
This was the view from Yosemite National Park in California early AM Saturday after nearly 2ft. of snow came down in parts Sierras since late last week.
WOW! The 500mb level showed a near 100kt+ wind over southern California on Saturday morning. This type of intense wind will help to make the storm system even stronger over the coming days!
Storm Pushes East
The same storm system that brought rain and snow to places in the west will continue to move slowly into the central part of the country. Heavy rain and severe weather appears to be the main threat going forward through the rest of the weekend/early next week.
Severe Threats Continue
A multi-day severe weather threat continues through early next week as a powerful Pacific storm continues to wobble east. The image below was from Goldboro, NC as our last storm system departed the Eastern Seaboard.
Friday's Storm Reports
2014 Tornado Reports
Thanks to all of the tornado reports in North Carolina on Friday, the 2014 PRELIMINARY tornado reports through April 25th have climbed to 118. According to NOAA's SPC, the 118 PRELIMINARY tornado reports through April 25th is the lowest number of reports the 2005-2014 reports below. Last year saw 226 tornado reports, while in 2012, there were 588 reports.
Strong Pacific Storm Moves Inland...
The loop below from AM Saturday to AM Tuesday shows our latest strong Pacific storm working into the central U.S. with several rounds of severe weather potential.
Severe Threat Sunday
Sunday's severe threat looks quite interesting across the mid-section of the nation. A MODERATE RISK of severe weather has been issued in parts of the middle and lower Mississippi Valley. Hail, high winds and even tornadoes can't be ruled out. Stay aware of the weather situation if you live in these areas Sunday!!
...NEB...IA...NERN KS...NWRN MO... SEVERE STORMS ARE EXPECTED TO FORM BY EARLY AFTERNOON AHEAD OF THE SURFACE LOW. COLD TEMPERATURES ALOFT AND FAVORABLY ORIENTED DEEP-LAYER SHEAR VECTORS ACROSS THE DRYLINE WILL SUPPORT NWD MOVING SUPERCELLS CAPABLE OF LARGE HAIL AND A FEW TORNADOES.
...ARKLATEX INTO SRN MO... STRONG INSTABILITY WILL DEVELOP AHEAD OF THE DRYLINE AS MID TO UPPER 60S DEWPOINTS SURGE NWD AND HEATING OCCURS. DEEP-LAYER SHEAR WILL BE PERFECTLY ORIENTED RELATIVE TO THE DRYLINE FOR DISCRETE SUPERCELLS. GIVEN THE DEGREE OF BOUNDARY LAYER CONFLUENCE AHEAD OF THE DRYLINE...AND STRONG HEATING AND MOISTENING...A PRE-FRONTAL BAND OF SUPERCELLS COULD FORM OVER SRN AR...NRN LA...AND NERN TX. SUPERCELLS WILL INITIALLY BE CAPABLE OF VERY LARGE HAIL...WITH AN INCREASING TORNADO THREAT AS THEY MATURE DURING THE LATE AFTERNOON AND EVENING. SEVERAL STRONG TORNADOES APPEAR POSSIBLE...AND A HIGH RISK COULD BE ISSUED IN SUBSEQUENT OUTLOOKS ONCE CONFIDENCE IN THE BEST CORRIDOR INCREASES.
Monday Severe Threat
The Storm Prediction Center has issued another MODERATE RISK on Monday just east of Sunday's MODERATE RISK area. Monday could feature another day with tornadoes...
...MIDWEST TO CNTRL GULF COAST...
A PLUME OF 60S SURFACE DEW POINTS WILL BE ESTABLISHED FROM THE WARM FRONT IN THE MIDWEST S/SWWD TO THE WRN/CNTRL GULF COAST AND PERSIST AMIDST STRONG LOW-LEVEL S/SWLYS. ALTHOUGH CONVECTION WILL LIKELY BE ONGOING AT 12Z/MON FROM PARTS OF THE MIDWEST TO MID-SOUTH...ROBUST DIURNAL HEATING SHOULD OCCUR IN CONVECTIVE-FREE AREAS TO SUPPORT AT LEAST MODERATE BUOYANCY OVER MUCH OF THE WARM SECTOR BY AFTERNOON. LOW/DEEP-LAYER SHEAR WILL BE QUITE STRONG OWING TO THE AFOREMENTIONED SPEED MAX. THIS CO-LOCATION WITH THE ESTABLISHED WARM SECTOR YIELDS A LARGE AREA OF ORGANIZED SEVERE POTENTIAL. THE MOST CONCENTRATED CORRIDOR FOR HIGH-END SEVERE RISK APPEARS CENTERED OVER PARTS OF THE LOWER MS VALLEY TO MID-SOUTH. WIDESPREAD STORMS APPEAR PROBABLE DURING THE AFTERNOON...LIKELY EMANATING FROM REGENERATIVE CONVECTIVE CLUSTERS ALONG THE DRYLINE/CONVECTIVE OUTFLOWS. WITH EFFECTIVE SHEAR AOA 50 KT AND SURFACE DEW POINTS INTO THE MIDDLE TO UPPER 60S...SETUP COULD YIELD SEVERAL SUPERCELLS WITH STRONG TORNADOES AND LARGE HAIL...EVOLVING INTO BOWS AND WIDESPREAD DAMAGING WINDS.
Severe Threat Tuesday
..DISCUSSION... THE MULTI-DAY SEVERE WEATHER EPISODE ASSOCIATED WITH THE PERSISTENT UPPER-LEVEL TROUGH OVER THE CNTRL CONUS SHOULD CONTINUE INTO D4/TUE AS THE LAST IN A SERIES OF INTENSE MID-LEVEL SPEED MAXIMA EJECTS THROUGH THE BASE OF THE TROUGH. THIS SHOULD RESULT IN STRONG KINEMATIC FIELDS OVERSPREADING A GULF WARM SECTOR CHARACTERIZED BY 60S SURFACE DEW POINTS. THE BREADTH OF THE WARM SECTOR WILL PROBABLY BE CONFINED BY WIDESPREAD ANTECEDENT CONVECTION ON D3. HOWEVER...GUIDANCE IS FAIRLY CONSISTENT WITH DIURNAL DESTABILIZATION OCCURRING AHEAD OF THE PACIFIC COLD FRONT/EFFECTIVE DRYLINE. THE CAPE/SHEAR COMBINATION APPEARS FAVORABLE FOR HIGHER-END SEVERE RISK FOCUSED FROM THE CNTRL OH VALLEY TO THE CNTRL GULF COAST. OVERALL KINEMATIC FIELDS SHOULD BE IN A WEAKENING STATE ON D5/WED AND BECOME INCREASINGLY DISPLACED FROM GREATER BUOYANCY AS THE FRONT ACCELERATES EWD. NEVERTHELESS...ORGANIZED SEVERE POTENTIAL IS EVIDENT FROM PARTS OF THE CNTRL APPALACHIANS AND MID-ATLANTIC SWD TO THE SOUTHEAST...LIKELY YIELDING EVENTUAL SLIGHT RISK DELINEATION.
Cut-Off Low Develops
The storm system becomes mature early this week. It intensifies so much that it becomes "Cut-off" from the upper level winds. This tends to keep weather systems stagnant. Weather conditions in the eastern two-thirds of the nation through much of the week ahead.
Wet Weather Ahead
According to NOAA's HPC, the 5 day precipitation forecast looks quite wet for a number of locations east of the Rockies. Some spots could wind up with 2" to 5" of rain by the end of next week!
Thanks again for checking in and have a great rest of your weekend and stay safe!